The invention relates to a device for removing projecting parts, such as burls, ridges and the like, from tires (trimming device) and similar workpieces by embrittlement and breaking of these parts. Tires of different sizes can be successively processed without any order, with a mounting frame or housing, which contains an embrittlement device, i.e., a cooling device and a breaking tool as well as devices which perform the isolating, gripping, conveying and processing movement of the tires in the housing.
Tires are produced by vulcanization of a corresponding initial material in molds. In this case, the excess initial material is driven out from the shaping mold in the production process and remains solidly connected to the tire product in the form of elongated burls extending from the surface of the tire. But these burls as well as other projecting parts and ridges from the production process must be removed for the final completion of the produced tire.
For this purpose, cutting off these burls with special cutting tools has been conventional, but the tool changing time, occurring with the wear of the cutting tools as well as imperfect processing because of inexact guiding of the cutting tools along the tire circumference cause problems.
A device based on the processing principle of cold embrittlement and breaking is known from DE-OS 31 50 901. According to this laid-open specification, the removal of the projecting parts and burls takes place by partial immersion of the tires in a coolant and the resulting embrittlement of these burls and ridges, which are then removed by special tools. The separation of the burls and ridges takes place according to the laid-open specification especially by pneumatically controlled rollers or stripping straps. Mainly the treads of the tires, as well as the areas laterally adjacent to them, can be processed with these breaking tools. In this case, these tools, on the one hand, have the drawback that they process the tires virtually only "in spots", on the point of contact of the tool and tread, and thus each point of the tire has to be coated several times for a satisfactory processing. A considerable processing time, which cannot be shortened, results from this. On the other hand, the adaptability of these tools, i.e., the roller and strap type tools, is limited by the combination of tire contour and width, since such tools can be designed for any width but not to match the contours of different tire sizes. As a result, processing defects often result on the side surfaces adjacent to the tread of the tires.
Therefore, in devices according to DE-OS 31 50 901, qualitative problems result such as problems in regard to short cycle times because of the processing periods that cannot be shortened. Further, devices of this type, when in continuous operation, require a back and forth movement of the coolant bath per tire to be processed, which presents an additional problem, especially with short cycle times, because of the so-called sloshing effects of the coolant.
But in general, processing based on the principle of embrittlement and breaking has proven to be perfectly favorable.